The present invention relates to an apparatus for automatically cleaning an impression cylinder of an offset sheet-fed press without manual operation.
In the known art, it is difficult to manually carry out cleaning for an impression cylinder of an offset sheet-fed press because there is less space around the impression cylinder arranged in the offset sheet-fed press and, accordingly, the manual cleaning working of the impression cylinder takes much time and labor for the worker. In order to obviate such a defect, there is provided a cleaning apparatus, as disclosed in Japanese Patent Laid-open Publication No. 63-92456 (92456/1988), in which a cleaning cloth is pressed at its rear surface to the surface of the impression cylinder by utilizing a blade.
In one example of the conventional cleaning apparatus, a cleaning cloth for cleaning an impression cylinder is moved stepwisely from a magazine roll to a wind-up roll and, simultaneously, the rear surface of the cleaning cloth is press contacted to the surface of the impression cylinder by means of a blade member, for example, while supplying a cleaning liquid. A guide member is disposed on the side of the wind-up roll so that a portion of the cleaning cloth press-contacted by the blade member maintains an arcuate contact condition along the outer surface of the impression cylinder between the blade and a guide member. The impression cylinder has a gripper member secured to a gripper shaft for holding an end portion of a sheet and a gripper escape cam is secured to the gripper shaft for preventing the gripper member projected from the surface of the gripper shaft from contacting the cleaning cloth.
The conventional cleaning apparatus of the structure described above is constructed such that the whole structure of the apparatus is rotated about a pivot axis to thereby press-contact the cleaning cloth to the impression cylinder by means of the blade member and a cleaning liquid ejection nozzle is assembled inside the apparatus. Such a cleaning apparatus is arranged as a whole at an upper portion of the impression cylinder.
However, in the sheet-fed press, it is first necessary to manually carry out the positioning operation of the blade to make uniform the precise application of the contact pressure of the blade to the impression cylinder. Moreover, the design of an attaching bracket and a body of the offset sheet-fed press must be changed in accordance with the difference of the diameters of the impression cylinders to be used and with the change of the layout of the cylinder. Furthermore, when the cleaning apparatus is arranged in the upper portion of the impression cylinder, it is necessary to pay attention to interference between the cleaning apparatus and the end portion of the sheet at the printing operation.